2-(2,4-Dichloro­phen­yl)acetic acid

Abstract

In the title compound, C₈H₆Cl₂O₂, the dihedral angle between the C—C(=O)—OH carboxyl unit and the benzene ring is 70.70 (4)°. In the crystal, mol­ecules are linked into inversion dimers by pairs of O—H⋯O hydrogen bonds. The dimers are linked into chains extending along [001] by weak C—H⋯Cl inter­actions.

Related literature

For background to carboxylic acids as supra­molecular synthons, see: Thalladi et al. (1996 ▶). For related structures, see: Hodgson & Asplund (1991 ▶); Li et al. (2010 ▶).

Experimental

Crystal data

• C₈H₆Cl₂O₂

• M _r = 205.03

• Monoclinic,

• a = 10.824 (2) Å

• b = 5.6061 (11) Å

• c = 13.820 (3) Å

• β = 91.08 (3)°

• V = 838.4 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.72 mm⁻¹

• T = 113 K

• 0.24 × 0.20 × 0.12 mm

Data collection

• Rigaku Saturn CCD diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.846, T _max = 0.918

• 5321 measured reflections

• 1484 independent reflections

• 1237 reflections with I > 2σ(I)

• R _int = 0.037

Refinement

• R[F ² > 2σ(F ²)] = 0.027

• wR(F ²) = 0.075

• S = 1.10

• 1484 reflections

• 111 parameters

• H-atom parameters constrained

• Δρ_max = 0.23 e Å⁻³

• Δρ_min = −0.22 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1i	0.82	1.85	2.6689 (16)	175
C4—H4⋯Cl1ii	0.93	2.86	3.731 (2)	156

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Carboxylic acid is a supramolecular synthon, widely used to construct supramolecular array with one to three different dimensions via hydrogen bonds (Thalladi et al., 1996). For our continuous research, we herein report the structure of the title compound (I).

In the title molecule, (Fig 1), the O1/O2/C7/C8 carboxyl unit forms an angle of 70.70 (4) A with the benzene ring. In the crystal packing, the molecules are linked into dimers by strong O—H···O H-bonding, which extend down the c axis by the aid of weak C—H···Cl H-bonding (Table 1 & Fig 2). For related structures, see: Hodgson & Asplund (1991) and Li et al. (2010).

Experimental

The title compound was available from Hunan institute of Chemical Industry, received without further purification. Colourless blocks of (I) were obtained by evaporation from its solution of ethyl acetate/petroleum ether 1/2 (v/v).

Refinement

All H atoms were positioned geometrically and constrained to ride on their parent atoms [C—H distances are 0.93 and 0.97Å with U_iso(H) = 1.2 U_eq(C) for aromatic and CH₂ H atoms, 0.82Å with U_iso = 1.5U_eq (O) for hydroxyl H atom].

Figures

Fig. 1.

The molecular structure of (I) showing displacement ellipsoids drawn at the 50% probability level.

Fig. 2.

The infinite chain formed via alternative O—H···O and C—H···Cl hydrogen bonding down the c axis.

Crystal data

C8H6Cl2O2	F(000) = 416
Mr = 205.03	Dx = 1.624 Mg m−3
Monoclinic, P21/n	Melting point = 403–405 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 10.824 (2) Å	Cell parameters from 2684 reflections
b = 5.6061 (11) Å	θ = 2.4–27.9°
c = 13.820 (3) Å	µ = 0.72 mm−1
β = 91.08 (3)°	T = 113 K
V = 838.4 (3) Å3	Block, colourless
Z = 4	0.24 × 0.20 × 0.12 mm

Data collection

Rigaku Saturn CCD diffractometer	1484 independent reflections
Radiation source: rotating anode	1237 reflections with I > 2σ(I)
confocal	Rint = 0.037
Detector resolution: 7.31 pixels mm-1	θmax = 25.0°, θmin = 2.4°
ω and φ scans	h = −12→12
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	k = −6→6
Tmin = 0.846, Tmax = 0.918	l = −10→16
5321 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027	H-atom parameters constrained
wR(F2) = 0.075	w = 1/[σ2(Fo2) + (0.0435P)2] where P = (Fo2 + 2Fc2)/3
S = 1.10	(Δ/σ)max = 0.001
1484 reflections	Δρmax = 0.23 e Å−3
111 parameters	Δρmin = −0.22 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.073 (5)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.71462 (4)	0.15511 (7)	0.45827 (3)	0.02309 (18)
Cl2	0.35390 (4)	0.34376 (7)	0.70900 (3)	0.02349 (18)
O1	0.55180 (10)	0.4443 (2)	0.88848 (8)	0.0230 (3)
O2	0.46215 (12)	0.7778 (2)	0.94126 (8)	0.0266 (3)
H2	0.4593	0.7022	0.9920	0.040*
C1	0.67428 (16)	0.6663 (3)	0.65565 (12)	0.0196 (4)
H1	0.7191	0.7977	0.6777	0.024*
C2	0.72229 (14)	0.5277 (3)	0.58229 (11)	0.0203 (4)
H2A	0.7977	0.5660	0.5551	0.024*
C3	0.65595 (15)	0.3314 (3)	0.55033 (11)	0.0166 (4)
C4	0.54302 (14)	0.2735 (3)	0.58966 (11)	0.0176 (4)
H4	0.4990	0.1408	0.5680	0.021*
C5	0.49744 (14)	0.4168 (3)	0.66162 (11)	0.0165 (4)
C6	0.56134 (14)	0.6155 (3)	0.69727 (11)	0.0155 (4)
C7	0.51115 (15)	0.7662 (3)	0.77720 (11)	0.0188 (4)
H7A	0.5601	0.9107	0.7826	0.023*
H7B	0.4272	0.8125	0.7601	0.023*
C8	0.51103 (15)	0.6439 (3)	0.87375 (12)	0.0173 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cl1	0.0220 (3)	0.0288 (3)	0.0187 (3)	0.00182 (16)	0.00584 (19)	−0.00592 (16)
Cl2	0.0160 (2)	0.0273 (3)	0.0274 (3)	−0.00391 (15)	0.00862 (19)	−0.00387 (17)
O1	0.0288 (6)	0.0256 (7)	0.0146 (6)	0.0115 (5)	0.0033 (5)	−0.0024 (5)
O2	0.0387 (8)	0.0245 (7)	0.0168 (6)	0.0114 (6)	0.0075 (6)	−0.0012 (5)
C1	0.0210 (9)	0.0183 (9)	0.0195 (9)	−0.0041 (6)	0.0008 (8)	0.0001 (7)
C2	0.0158 (8)	0.0250 (9)	0.0203 (9)	−0.0023 (7)	0.0046 (7)	0.0027 (7)
C3	0.0194 (8)	0.0192 (9)	0.0114 (8)	0.0035 (7)	0.0018 (7)	0.0015 (6)
C4	0.0179 (8)	0.0182 (8)	0.0168 (8)	−0.0013 (7)	−0.0004 (7)	−0.0024 (7)
C5	0.0130 (8)	0.0213 (8)	0.0153 (8)	−0.0004 (6)	0.0017 (6)	0.0047 (7)
C6	0.0193 (8)	0.0161 (8)	0.0111 (8)	0.0013 (6)	−0.0003 (7)	0.0028 (6)
C7	0.0210 (8)	0.0163 (8)	0.0191 (9)	0.0007 (7)	0.0004 (7)	−0.0005 (7)
C8	0.0135 (8)	0.0232 (10)	0.0151 (8)	0.0003 (6)	0.0017 (7)	−0.0044 (6)

Geometric parameters (Å, °)

Cl1—C3	1.7405 (16)	C2—H2A	0.9300
Cl2—C5	1.7460 (16)	C3—C4	1.386 (2)
O1—C8	1.2185 (19)	C4—C5	1.377 (2)
O2—C8	1.316 (2)	C4—H4	0.9300
O2—H2	0.8200	C5—C6	1.396 (2)
C1—C2	1.386 (2)	C6—C7	1.501 (2)
C1—C6	1.390 (2)	C7—C8	1.500 (2)
C1—H1	0.9300	C7—H7A	0.9700
C2—C3	1.382 (2)	C7—H7B	0.9700
C8—O2—H2	109.5	C4—C5—Cl2	117.86 (12)
C2—C1—C6	122.16 (15)	C6—C5—Cl2	119.55 (13)
C2—C1—H1	118.9	C1—C6—C5	116.81 (15)
C6—C1—H1	118.9	C1—C6—C7	121.50 (14)
C3—C2—C1	118.72 (15)	C5—C6—C7	121.68 (15)
C3—C2—H2A	120.6	C8—C7—C6	113.81 (13)
C1—C2—H2A	120.6	C8—C7—H7A	108.8
C2—C3—C4	121.21 (15)	C6—C7—H7A	108.8
C2—C3—Cl1	119.43 (13)	C8—C7—H7B	108.8
C4—C3—Cl1	119.36 (12)	C6—C7—H7B	108.8
C5—C4—C3	118.50 (15)	H7A—C7—H7B	107.7
C5—C4—H4	120.7	O1—C8—O2	123.67 (16)
C3—C4—H4	120.7	O1—C8—C7	124.19 (15)
C4—C5—C6	122.59 (15)	O2—C8—C7	112.14 (13)
C6—C1—C2—C3	−0.6 (2)	C4—C5—C6—C1	0.9 (2)
C1—C2—C3—C4	0.5 (2)	Cl2—C5—C6—C1	−179.10 (11)
C1—C2—C3—Cl1	179.98 (12)	C4—C5—C6—C7	−178.68 (14)
C2—C3—C4—C5	0.2 (2)	Cl2—C5—C6—C7	1.3 (2)
Cl1—C3—C4—C5	−179.22 (11)	C1—C6—C7—C8	−109.95 (17)
C3—C4—C5—C6	−1.0 (2)	C5—C6—C7—C8	69.59 (19)
C3—C4—C5—Cl2	179.02 (11)	C6—C7—C8—O1	2.7 (2)
C2—C1—C6—C5	−0.1 (2)	C6—C7—C8—O2	−177.59 (13)
C2—C1—C6—C7	179.49 (14)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1i	0.82	1.85	2.6689 (16)	175
C4—H4···Cl1ii	0.93	2.86	3.731 (2)	156

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+1, −y, −z+1.